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    The original part of the drainage system in my house is cast iron. Night before last a leak developed under one of the fittings. A ¼” hole had rusted through in a horizontal 45deg fitting. While wiping it dry with a paper towel, the hole enlarged to about 1” X ¼”. I did a temp repair with epoxy putty and some Fiberglas mesh which should hold it for a while, but this tells me that I should replace the old cast iron fittings before I have a major catastrophe in the middle of the night. I wish to replace with PVC. I have a straight run of PVC from my sink which connects to a 2” galv. pipe stub with a fernco coupling. the pipe stub is attached to the rusted out 45 deg. cast iron elbow which goes into a 45 deg. ‘Y’. That ‘Y’ then goes into a 4” cast iron horizontal soil stack. The old connections are made with lead and oakum. I wish to replace the galv. stub and the two 45 deg. cast iron fittings with PVC. Is there some type of connector which permits attaching PVC into the side hub of the soil stack? If I cut off the ‘Y’ where it enters the soil stack, will I be able to dig out the old oakum and lead?

  • #2
    Q1: Is there some type of connector which permits attaching PVC into the side hub of the soil stack?

    A: Yes, but don't remember the name. Fernco and others make connectors to transition from CI Soil Pipe to PVC, copper, or whatever. You probably won't find them at HD, you need to visit a real plumbing supply house.

    Q2: If I cut off the ‘Y’ where it enters the soil stack, will I be able to dig out the old oakum and lead?

    A: Is there any pipe between the second 45 and the Fiting in the stack? Is it a combo or or a sanitary tee? If you do have some pipe and the connection into the stack is OK you could cut the pipe using an abrasive cutoff wheel or a snap cutter and make your connection there. Otherwise you could make two cuts in the stack above and below the connection and replace that with No-Hub CI Pipe and install a new fitting in the stack, then tie into your existing PVC.


    • #3
      I would cut above the wye fitting in the 4" stack and go back as far to the building drain that you feel comfortable with. Then I would use a 4" no hub clamp the ones with the four bands , not the ferncos or any two banded clamp. Make sure these clamps have 4 bands .Then I would work my way back using another 4" no hub clamp. I would use a PVC 4x2 wye and bush down the 2" branch to 1 1/2,its cheaper this way. Run your 1 1/2 line to your sink.

      There are alot of problems that could arise if the 4" stack isnt properly supported so be sure to hang with some perforated strapping before you cut into stack.

      Also the transition fitting that goes into the hub is called a Man-off which has to be joined by a lead pour.


      • #4
        I WENT through something similar to this about 6 mos ago. my stack rotted through and the sewage was seeping through the side of the cast iron. i made a few mistakes and it took me all day, but it was worth it. so here is my experience/two cents. first off, i was not aware of the fact that they made a snap cutter so i proceeded to cut the cast iron pipe out with a sawzall and an abrasive blade (actually five or six abrasive blades). the first lesson i learned was wear a dust mask! getting the lead and okum out was easy. it was as simple as using a drill and drilling out some of the lead, until i could get under it with a chisel, came out fairly easy.

        my other issue was that 2 toilets and my tub feed into the stack so i had 2 90's and a "t" to contend with. my biggest mistake was hooking the stack up to the cast iron which goes up to the 2nd story toilet and vent. i was not aware that they made a fitting specifically for this, so i used a 4" coupling, a dremel, and a lot of brute force and ignorance to get the pvc to mate up with the cast iron. so much so, i had to cut it in two pieces and use a coupling so i had more flexibility. this was a pain as anyone who knows of the fitting i am speaking of is well aware.

        learned a lot from that job, and hope i never have to do it again!


        • #5
          one last thing. quickrete hydro stop is a wonderful product (i think it is called hydro stop). used in place of the lead on top of the okum and this stuff is great!!! much easier than lead, especially on a vertical joint!


          • #6
            A note on using a snap cutter on installed pipe:

            when both ends of the pipe are fixed (can't move) you need to be a little more careful using a snap cutter. Make sure both side of the cut are supported, there's a lot of weight there especically in a stack. Place the snap cutter around the pipe and ensure that the chain is square to the pipe as possible(this is tougher when cutting into a stack, you need to support the weight of the cutter). Score the outside of the pipe using the snap cutter by rotating it a few degrees and applying some pressure (but not enough to snap the pipe). Do this until you have a good clear mark scored around the pipe and you should have little trouble making a clean cut. Because both ends are fixed there is no place for the pipe to go when the cut is made. Remember you don't actually remove any material when making a 'cut' in CI pipe, you are seperating it into two pieces, like snapping a piece of glass tubing. The cutter wheels will displace the pipe to the left/right a fraction of an inch, doesn't seem like much but that 1/8" can induce stress in other places and cause a crack in an old or weak fitting.


            • #7
              Thanks for all the responses and advise. I may consider replacing all the cast iron including the soil stack extending through my roof. Since I can't see inside the wall in my living space, I wonder if it is customary to have the iron pipe supported within the walls? If that is the case then it would be unlikely that I could remove the stack even if it were cut free in my basement. Any comments?


              • #8
                It should be supported along the way up thru the ceiling level of the top floor.

                You can install a riser clamp above where you want to cut in the basement (or wherever it is) and securely support the riser clamp either by installing two 3/8" hanger bolts and running a length of 3/8 rod down to the riser clamp placing a nut and washer above and below the riser clamp -or- you could support it from below somehow but using the riser clamp as I mentioned above it probably best. Careful not to crush the pipe since it is old and already know to be weak in spots.

                Replacing the entire stack above where you make the cut is not a bad idea but more work of course.